This invention relates to power generation apparatus employing one or more blades which move under the influence of a fluid stream to produce an output force capable of performing useful work. For example, the apparatus may be used to power a pump or to reciprocate or rotate a shaft. The invention relates especially to such apparatus whose blade(s) oscillates instead of rotates in the presence of a wind or water stream to produce an output torque for driving an electric generator to provide grid quality power to a utility grid or to a remote off grid community, for example. A method for generating power in this fashion is also part of my invention.
Conventional hydro-electric power generators usually comprise large rotating element water turbines requiring their own power house and extensive civil engineering works, and which require a large pressure head to be effective which, in turn, demands a high dam for creating this potential energy; the dam is also useful for storing a large amounts of this water energy. None of these large conventional hydro-electric power generators are suitable for operating in the shallow waters found in most rivers and tidal flows. As a result, hydroelectric water projects that utilize the entire river flow tend to be quite large thereby consuming large amounts of real estate and capital, while displacing  whole populations of people with wholesale disruption of the local environment and the natural migration of fish.
There are many locations, usually conveniently near large inland and some coastal cities which are the major consumers of electric power, where a large mass of relatively shallow water flows in a constant and reliable manner under a relatively low pressure head at relatively low velocity, generally in areas of relatively flat terrain, which may not be suitable for efficiently driving a conventional water turbine. These include the fresh water currents in various rivers and streams throughout the world such as the Mississippi and Amazon Rivers, as well ocean currents such as Gulf Stream and the tidal currents in places like the Bay of Fundy.
Likewise, conventional wind turbines are not practical or desirable in or near large urban or suburban neighborhoods where the power is consumed, because these machines are considered unsafe for these areas. Also, cities are not usually built where there are high winds and are only placed in large groups or farms at locations where they can be serviced efficiently and where they are exposed to relatively constant, high velocity winds. The areas where such windmill farms can be sited are limited both by the atmospheric conditions and by the safety and visual objections of people in the vicinity of the wind farms.
Thus, there is a need for a fluid responsive power generator and power generating method which can economically and safely extract useful power from relatively low head shallow waters and the more turbulent lower speed wind currents commonly found near major population centers and on flat terrain and to use that power to perform useful work such as the generation of electricity nearer the point of consumption,  thereby saving the environmentally degradation as well as the capitol expense and losses of power transmission systems.